This invention relates to a fluid shut-off valve and method for using same and more particularly to a shut-off valve which automatically shuts off the flow of fluid in the event of line breakage or blockage. Both mechanical as well as electro-mechanical automatic fluid shut-off valves have been known for some time. It is quite common, for example to install a pressure sensor in a fluid line to detect a high pressure fault caused by blockage or a low pressure fault caused by line rupture. The electrical control device would shut the system down in the event of a malfunction. Mechanical systems have been developed which automatically shut off the line in the event of a malfunction such as the valves shown in U.S. Pat. Nos. 2,508,399; 2,664,101; or 3,568,705. A drawback of prior art mechanical shut-off valves require expensive pressure transducers and expensive reprogramming of the electrical controller.
In industrial applications where many bearing points must be lubricated, it is common to have a single pump for a fluid lubricant servicing many bearing points. In order to carefully meter the lubricant going to each bearing point, it is common to use a divider valve such as the type sold under the trademarks TRABOND-MANZELL.RTM. made by Houdaille Industries and described in product brochure No. 10102 which is incorporated by reference herein. Using one or more divider valves, a large centralized lubrication system can be run off a single pump servicing hundreds of bearing points. A divider valve sequentially directs the output of the pump to each bearing point delivering a predetermined volume of lubricant. If any of the bearing lines plug, the required volume of oil will not be delivered and the divider valve will stop cycling and a high-pressure fault will occur. A single-pressure transducer in the input divider valve can detect highpressure faults in any of the bearing lines. On the other hand, when there is a broken line, the divider valve will cycle normally unaffected by the low pressure in the line extending between the divider valve and the bearing point. It has previously been the practice to install pressure transducers to detect a low-pressure fault caused by a broken line in those lines in which fluid flow is extremely critical. Due to the high cost of pressure transducers and their related control systems, it is frequently not economically feasible to provide an electrical low-pressure fault sensor for each bearing point.
Another type of commonly used industrial lubrication system which needs a shut-off valve is a spray lubrication system sold under the trademark SPINDLE GUARD.TM.. A spray lubrication system typically uses a metered amount of lubricant which is injected into an air line causing the airlubricant mixture to be sprayed through a nozzle on a bearing point. Due to the compressibility of the air in the line in the event of a clogged nozzle, a high-pressure fault will not be detected by the standard lubrication system sensor since the divider valve will merely continue to pump oil in the clogged line compressing the gas therein.
It is therefore an object of this invention to provide a relatively inexpensive, reliable mechanical automatic shut-off valve for a fluidic system.
It is the further object of the this invention to provide an improved automatic shut-off valve which can be attached directly to a central lubrication system divider block to facilitate easy installation.
It is yet another object of the invention to allow an operator to quickly locate the defective fluid line once a fault has occurred. An important advantage of this invention is to provide an inexpensive mechanical shut-off valve with very few moving parts allowing for a reliable and low-cost valve.